In order to investigate tumor sterol metabolism in normal human liver as well as hepatoma lines, a serum-free culture system has been established for human hepatocytes. Lipoprotein binding studies have been instituted in a human hepatoma cell line as well as normal human liver. In vivo studies of Morris hepatoma 7777 have been initiated with animals receiving sterol synthesis inhibitor called Mevinolin. Two initial studies have been completed to establish the proper dosage interval and to investigate the effect of the drug on a key sterol synthetic enzyme. Additional data in this system includes information about total body sterol synthesis utilizing isotope methods previously established. The interaction of melanoma cells in culture with liposomes of varying molecular content has been investigated in an attempt to disclose unusual aspects of lipid processing by melanoma cells.